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Ch. 6 - Stereoisomerism: Arrangement of Atoms in Space
Mullins - Organic Chemistry: A Learner Centered Approach 1st Edition
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471Not the one you use?Change textbook
All textbooksMullins 1st EditionCh. 6 - Stereoisomerism: Arrangement of Atoms in SpaceProblem 35b
Chapter 5, Problem 35b

For the molecules shown,
(i) count the number of stereocenters present and
(ii) draw all possible stereoisomers.
(iii) Identify the relationships between stereoisomers as enantiomers or diastereomers.
(b) Structural representation of a molecule with hydroxyl and thiomethyl groups, highlighting potential stereocenters.

Verified step by step guidance
1
Step 1: Begin by identifying stereocenters in the molecule. A stereocenter is typically a carbon atom bonded to four different groups. Carefully examine each carbon atom in the molecule and determine if it meets this criterion.
Step 2: Count the total number of stereocenters present in the molecule. Use the formula for calculating the maximum number of stereoisomers: \( 2^n \), where \( n \) is the number of stereocenters.
Step 3: Draw all possible stereoisomers. For each stereocenter, assign configurations (R or S) based on the Cahn-Ingold-Prelog priority rules. Systematically vary the configurations to generate all combinations.
Step 4: Compare the stereoisomers to determine their relationships. Two stereoisomers that are non-superimposable mirror images are enantiomers, while stereoisomers that are not mirror images are diastereomers.
Step 5: Summarize the relationships between the stereoisomers. Clearly label each pair as enantiomers or diastereomers based on their structural and spatial arrangements.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Stereocenters

A stereocenter, or chiral center, is a carbon atom that is bonded to four different substituents, leading to non-superimposable mirror images known as enantiomers. The presence of stereocenters in a molecule is crucial for determining its stereochemistry and the number of possible stereoisomers. Each stereocenter can exist in two configurations, contributing to the overall stereoisomer count.
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Stereoisomers

Stereoisomers are compounds that have the same molecular formula and connectivity of atoms but differ in the spatial arrangement of their atoms. They can be classified into two main types: enantiomers, which are non-superimposable mirror images, and diastereomers, which are not mirror images of each other. The number of stereoisomers for a molecule can be calculated using the formula 2^n, where n is the number of stereocenters.
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Enantiomers and Diastereomers

Enantiomers are pairs of stereoisomers that are mirror images of each other, exhibiting different optical activities. In contrast, diastereomers are stereoisomers that are not related as mirror images and often have different physical properties. Understanding the relationships between stereoisomers is essential for predicting their behavior in chemical reactions and biological systems.
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Related Practice
Textbook Question

How many stereoisomers are possible for each of the following molecules?

(c)

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Textbook Question

How many stereoisomers are possible for each of the following molecules?

(a)

1284
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Textbook Question

(S)-Propranolol, a drug used for the treatment of anxiety, has a specific rotation of -25.5° . Attempting to prepare it in enantiopure form, a chemist produced a compound that gave a specific rotation of -18.3° . What is the ratio of (S)- to (R)-propranolol produced by the chemist?

1026
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Textbook Question

(R)-Selegiline, a monoamine oxidase (MAO) inactivator, was approved by the FDA in 1989 for the treatment of Parkinson's disease. In pure form, it has a specific rotation, [α]²⁰D = - 11.0°. What is the expected specific rotation of a mixture containing 64% S and 36% R?

881
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Textbook Question

For the molecules shown,

(i) count the number of stereocenters present and

(ii) draw all possible stereoisomers.

(iii) Identify the relationships between stereoisomers as enantiomers or diastereomers.

(c)

919
views
Textbook Question

For the molecules shown,

(i) count the number of stereocenters present and

(ii) draw all possible stereoisomers.

(iii) Identify the relationships between stereoisomers as enantiomers or diastereomers.

(a)

1508
views